Progress in signal transduction of erythropoietin

Erythropoietin is a critical growth factor in development of erythrocyte. After binding to its receptor, eryhropoietin produces biological action through consequent activation of intracellular signal transduction systems, including JAK2-STAT5, sos-Ras-MAPK, IRS-2-PI₃-K⁺ and Ca²⁺ channel.     

A reactive pattern of ischemia-induced nestin protein in the rat brain

AIM:To explore the expressive profile of nestin protein in the focal ischemic brain and to study the recovery mechanism of brain focal infarct.METHODS:Cellular morphology,time-course and distribution pattern of nestin positive response were immunohistochemically examined in different brain regions of 36 adult male SD rats. RESULTS:Nestin positive response of different brain regions in sham operated rats was present in small- and micro-vasculartures and the third ventricle bottom and ependyma. A large number of nestin positive cells were detected in ischemic brain, and were more remarkable in the cortical areas of parietal lobe and preoptic area as well as ischemic caudoputamen. Stellate nestin positive cells were located in the deep layer of ischemic cortex, but fibrillary cells were located in the shallow layer. Nestin positive cells in the ischemic caudoputamen showed the same changes of morphology as those cells in the deep layer of ischemic cortex. Morphological and number alterations of nestin positive cells were the most remarkable at 1 weeks post-ischemia, which showed more hypertrophy and proliferation in morphology, and a marked increase in number was present in the ischemic cerebral cortex and the ischemic caudoputamen. These alterations of nestin positive cells persisted up to 6 weeks post-ischemia, and then, the nestin positive response in the ischemic brain decreased gradually.CONCLUSION:Focal cerebral ischemia induces nestin re-expression on reactive astrocytes, which may be very important to the self-recovery of cerebral infarct.     

仔猪日粮中添加复合酸化剂的饲喂效果

选择7日龄哺乳仔猪126头，在玉米—豆粕型日粮中，分别添加6种自行研制的复合酸化剂饲喂仔猪，酸化剂的主要成分是柠檬酸、延胡索酸、磷酸、乳酸、草酸、酒石酸。结果表明，断奶仔猪的日增重比对照组分别提高11．94％、14．03％、7．46％、7．46％、17．31％、12．24％；饲料转化率分别提高13．92％、25．26％、7．73％、11．35％、21．65％、11．86％。仔猪的腹泻率也降低了。     

丝兰属植物提取物降低鸡舍氨气浓度的效果试验

通过在21日龄的肉用仔鸡饲料中添加丝兰属植物提取物(其有效成分为丝兰皂角苷)，研究丝兰属植物提取物对降低鸡舍中氨气浓度和提高肉仔鸡生产性能的效果。试验结果表明，试验组鸡舍内氨气平均浓度为4．75mg／L，对照组鸡舍内氨气平均浓度为13．80mgl／L，试验组比对照组鸡舍内氨气平均浓度降低了9．05mg／L，经t检验，两鸡舍内氨气平均浓度差异显著(P＜0．05)，并且试验组比对照组饲料报酬提高了8.92％。     

Ginkgo biloba extract enhances c-jun expression and attenuates motoneuron death induced by root avulsion

AIM: To investigate the influence of Ginkgo biloba extract (EGb761) on c-jun expressions and motoneurons survival following root avulsion. METHODS: One hundred and eighty adult Sprague-Dawley female rats were randomly divided into control and EGb761 groups. Immediately after avulsion of C5-T1 nerve roots, the rats were injected ip with either 1 mL of EGb761 25 mg·kg^-1·d^-1 or the same volume of normal saline, and the treatment repeated everyday. At 4 h to 6 weeks following avulsion, the C7 spinal segments of all rats were collected and prepared for c-jun immunocytochemistry and neutral red stain. The numbers of c-jun positive and survival motoneurons were counted and compared between two groups at each time point. RESULTS: In control rats following avulsion, c-jun positive motoneurons appeared at 4 h, reached its maximum at 1 d and declined to 2 weeks. Avulsion-induced motoneurons death started at 2 weeks, climbed to its maximum at 4 weeks-6 weeks. In EGb761 treated rats, both numbers of c-jun positive and survival motoneurons were more than that in control group at each time point. CONCLUSION: EGb761 attenuates avulsion-induced motoneurons death, and this effect may be related to up-regulation of c-jun gene in avulsed motoneurons.     

胡杨内生真菌曲霉(Aspergillus sp.)链格孢(Alternaria sp.)的生理特性

采用接种法 ,对胡杨内生真菌曲霉 ( Aspergillus sp.)和链格孢 ( Alternaria sp.)在不同温度、p H、碳源、氮源、培养基及糖质量浓度下进行了生理实验研究。结果表明 :温度对两种菌株的生长和孢子产生具有明显的影响 ;曲霉 ( Aspergillus sp.) p H5～ 6时生长良好 ,而链格孢 ( Alternaria sp.) p H为 4～ 5时菌株生长良好 ,两种菌株均以蔗糖为主要碳源 ;菌丝干质量与培养基质量浓度呈正向关系。     

兰州市SO_2污染控制区优化规划方案的探讨

根据《大气法》第二十七条关于划定酸雨控制区和SO2 污染控制区的规定 ,为使兰州市SO2 控制区达到环境质量目标的要求 ,本文以 98年的污染源资料和气象资料为模拟对象 ,利用大气扩散模式 ,通过各个污染源对每个控制点浓度分担率的计算 ,以污染源的总削减两最小 (总排放量最大 )或总削减率最小为优化目标 ,列出了几种优化方案并利用线性规划的方法对各种结果进行了对比分析。为了使最终的优化结果切实可行 ,将点源的上界乘一经济技术指标值 ,既可以使控制区达到环境质量目标值 ,又充分体现了公平合理的原则。     

Advances in studying the differentiation into neurons of mesenchymal stem cells and their application

Mesenchymal stem cells (MSCs) are a population of multipotent cells that can proliferate and differentiate into marrow and non-marrow cell types, such as adipocytes, chondrocytes, myocytes, and so on. In recent years, many researchers have studied whether MSCs are capable of differentiation into neurons in vivo and ex vivo. The result that MSCs-derived neurons express NSE and NF, but don't express GFAP suggests MSCs can differentiate into neurons, some researchers have achieved success in promoting functional recovery in Pakinsons and transactional spinal cord injury rat models by use of MSCs-derived neurons. Therefore, MSCs-derived neurons will play an important role in the therapy for a variety of diseases of the nervous system.     

猪卵泡卵母细胞体外成熟与冷冻保存

研究了激素、猪卵泡液、不同类型血清对猪卵泡卵母细胞体外成熟的影响 ;比较了卵泡直径小于 2 mm、2～ 5 mm和大于 5 mm的卵母细胞体外成熟能力的差异 ,并对不同发育阶段猪卵母细胞的冷冻保存进行了研究。结果表明 :猪卵母细胞体外培养 4 8h时 ,培养的前 2 4 h培养液中加入激素 ,后 2 4 h去掉激素 ,卵母细胞的 A级成熟率 (5 1.73% )和总成熟率 (83.2 5 % )最高 ,极显著高于前 2 4 h不加激素 ,后 2 4 h添加激素培养的成熟率 (P<0 .0 1) ;也显著高于不含激素的培养液连续培养 4 8h的成熟率 (P<0 .0 5 ) ;但与添加激素连续培养 4 8h的成熟率差异不显著 (P>0 .0 5 )。在体外成熟培养液中 ,添加 10 % (体积分数 ) ECS的成熟率 (72 .86 % )显著高于添加 10 % (体积分数 ) NCS的成熟率(6 2 .2 1% ) (P<0 .0 5 ) ,而添加 10 % p FF则抑制卵母细胞的体外成熟。随着卵泡直径的增大 ,卵母细胞体外成熟能力逐渐增强。采用程序冷冻保存方法 ,成熟卵母细胞的成活率 (35 .5 9% )显著高于培养前 (2 4 .6 4 % )和培养 2 4 h(2 3.36 % ) (P<0 .0 5 )。培养 2 4 h(77.2 2 % )和培养成熟 (72 .81% )的卵母细胞解冻后的形态完整率均显著高于培养前(5 3.2 4 % ) (P<0 .0 5 )     

生物牛黄中间体的抗病毒作用及对家兔血液流变学指标的影响

运用比较药理学方法研究了生物牛黄中间体与天然牛黄、人工牛黄在抗病毒及对家兔血液流变学指标影响方面的不同。结果显示，生物牛黄中间体以25、50、100mg／kg体质量及人工牛黄50mg／kg体质量灌胃给药的大鼠含药血清，灭活后，在10倍稀释的情况下，在鸡胚成纤维细胞上使新城疫Ⅰ系疫苗毒的TCID50升高1个滴度；生理盐水组、天然牛黄50mg／kg体质量组10倍稀释大鼠含药血清，灭活后，在鸡胚戍纤维细胞上使新城疫Ⅰ系疫苗毒的TCID50降低1.5个滴度。生物牛黄中间体以25、50、100mg／kg体质量灌胃给药，可明显降低高分子右旋糖酐所致“血瘀”家兔的血沉值、血沉方程K值和红细胞聚集指数；天然牛黄50mg／kg体质量组对血沉值和血沉方程K值具有显著降低作用；人工牛黄50mg／kg体质量组时血沉值具有显著降低作用。